An image decoloring apparatus having an image reading function and an image decoloring function is known.
Before a decoloring process, the image decoloring apparatus reads a sheet on which characters and figures (hereinafter, referred to as a handwritten image) written with decolorable ink decolored when heated and an image formed with color material decolored at a temperature different from that of the decolorable ink are printed. Thereafter, the image on the sheet is decolored, and the sheet after the image decoloring is read again. As a result, the image decoloring apparatus acquires image data before and after the image decoloring process. The image decoloring apparatus separates image data corresponding to the handwritten image and image data corresponding to an image other than the handwritten image based on the image data acquired before and after the image decoloring process.